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results when the same amount and kind of fertilizer applied broadcast 
is unprofitable, and the same remark applies to light applications on maize. 
One of the principal reasons for unprofitable results from plot tests 
is found in failure to make a distinction between the fertilization of crops 
producing high money values per acre, like truck and fruit, where the 
whole plant food supply muy be profitably secured from chemical manures, 
and such crops as wheat, oats and maize, where the chemical fertilizers 
must be used to supplement and balance the supplies from the soil, farm 
yard and legume field. The cost of full rations of commercial nitrogen 
can only occasionally be recovered in the wheat crop and rarely if ever 
in the case of oats and maize. Double ratious of phosphoric acid are often 
profitable and from one-half to full rations of potash. In most of the 
early plot experiments full rations were used, and sometimes the cost of 
the fertilizer for maize was greater than the total sum received for the 
crop even when the yields were good. 
Perhaps the contrast between the plot tests and the farm practice 
can be shown better in the form of the amounts per acre and the formula. 
In some of the wheat plot tests extending over twenty years the fertilizer 
is the equivalent of 500 pounds per acre of goods having formula of nitro- 
gen 10 per cent., phosphoric acid 5 per cent. and potash 6 per cent.; at the 
same time this series was started the common wheat fertilizer was 100 to 
200 pounds per acre of 2-8-2, which has gradually changed to 2-8-6; nitro- 
gen is sometimes increased to 3 per cent. The maize series of plots re- 
ceived the equivalent of 1,000 pounds per acre of a goods having a formula 
of nitrogen 12 per cent., phosphoric acid 4 per cent. and potash 6 per cent., 
while farm practice on maize uses 100 to 300 pounds per acre of goods 
having little or no nitrogen and containing from 5 to 10 per cent. phos- 
phorie acid and 4 to 10 per cent. of potash. For clay soils a common 
maize fertilizer is 0-10-4, for loams 0-8-8 and for black sandy soils 0-6-10, 
while on the peat or muck soils 100 pounds per acre of muriate of potash 
or its equivalent in kainit are commonly used. A small amount of nitro- 
gen is sometimes added, usually about 1 per cent.—rarely over 2. 
The cost per acre of the maize fertilization would be about $30 for 
the plot work and from $1 to $4 per acre for the fertilizers commonly used. 
The cost per acre of the wheat fertilization would be about $15 for the 
plot work and from $1 to $3 per acre for the fertilizers commonly used. 
In general it may be said that the fertilizers used on wheat and maize 
furnish about as much phosphoric acid as the crop removes, rarely as 
